In the past 30 years small boats have generally been constructed from two major materials, namely glass reinforced plastics (fiberglass) and sheet aluminium. Small fiberglass boats have the disadvantage that they are heavy and therefore difficult to handle, requiring high power and fuel for their propulsion, they are manufactured from materials which are arguably carcenogenic, they are flammable, suffer from osmosis and are difficult to repair when damaged. Aluminum boats are expensive due to the base cost of the material, are noisy in use due to wave pounding, suffer from dents and cracks in use and are prone to electrolysis.
Both fiberglass and aluminum small boats are labor intensive to manufacture and are expensive to transport to point of sale in bulk quantities. Neither fiberglass nor aluminum boats are particularly stable due to the design limitations imposed by the economic use of these materials.
A third type of small boat presently in the market is the inflatable or semi-rigid inflatable craft which has the advantage of being immensely stable and, because they can be deflated, are relatively easily transported. The main disadvantage and limiting factor of inflatable craft is that many are made by hand and are particularly expensive. If the craft are fully inflatable they usually do not ride very well in rough water as the hull bottom is relatively flat and pounds when it hits waves. If the craft has a rigid hull (semi-rigid inflatable craft), the hull is rigid and heavy and loses any ease of transport advantages of the fully inflatable craft. The flexible skirt and rigid hull are physically at odds with each other.
In prior art craft with inflatable tubes the tube surrounds both sides and the bow (and in some craft the stern as well). This has a number of disadvantages:
(1) cost is greatly increased because of the number of seams and angles and wasted fabric offcuts; PA0 (2) there is great room for error in construction; PA0 (3) the bow of the craft may have excessive bouyancy when travelling through waves (causing destructive stress in the center of the craft and impact shock to the passengers). PA0 (a) forming a hull bottom from thermoplastics material; PA0 (b) providing side skirts in the form of inflatable tubes; and PA0 (c) securing the side skirts to the hull bottom.
Attempts have been made in the past to overcome the labor intensive, and therefore expensive, method of manufacturing small boats by roto-moulding boats from various plastics materials. This method has never been very acceptable in the market place as the final product is heavy, very limited in design range and does not have a very long servicable life. Once again the end product is bulky and difficult to transport in large quantities to the point of sale.